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United States Patent | 5,156,460 |
Norling ,   et al. | October 20, 1992 |
A vibrating crystal transducer for measuring temperature is disclosed. The crystal includes a single elongated vibrating beam that has a torsional mode resonant frequency that is a function of the temperature of the crystal. The torsional moments of the crystal are reverse symmetric with respect to a nodal line on the beam. The beam is contained in a frame that is secured to a sensor frame member. The beam is attached to the frame by a pair of opposed mounting posts that are in line with the nodal line on the beam. The beam, the beam frame (16) and the mounting posts are formed out of an integral section of crystalline material. When the beam is vibrated, the reverse symmetrically opposed torsional moments along the beam cancel each other out and, consequently, no torsional energy is transmitted through the mounting posts to the beam frame or the sensor frame. Since the beam frame does not serve as a recipient for the torsional energy, torsional energy is not lost through the beam frame so that the beam has a relatively high quality factor and torsional vibration of the beam cannot cause the crystal to eventually work loose of the sensor frame at the beam frame.
Inventors: | Norling; Brian L. (Mill Creek, WA); Peters; Rex B. (Woodinville, WA) |
Assignee: | Sundstrand Corporation (Rockford, IL) |
Appl. No.: | 609247 |
Filed: | November 5, 1990 |
Current U.S. Class: | 374/117; 310/333; 310/368; 331/156 |
Intern'l Class: | G01K 011/22 |
Field of Search: | 310/333,361,368,338,367,320 331/66,154,156,153 374/117,118,119,183 |
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